1. Field of the Invention
The present invention relates to a paper feeding apparatus of an image forming device such as a laser printer, a copier, and an ink jet printer, and more particularly, to a paper feeding apparatus of an image forming device, which is capable of automatically opening a paper cassette into a paper feeding-standby position when the image forming device should be used, and automatically closing the paper cassette into a space-minimized position when the image forming device is not in use.
2. Description of the Related Art
FIGS. 1 and 2 show an ink jet printer as an image forming device. Generally, the ink jet printer has an ink cartridge 1 having a print head to jet ink to form an image on a sheet of paper P, a carrier 2 to move the ink cartridge 1 right and left, and a paper feeding apparatus 3, 4, 5, 6, 7, 8 to feed the sheet of paper P into the printer.
The paper feeding apparatus 3, 4, 5, 6, 7, 8 is composed of a paper cassette 3 to stack sheets of paper P, a pickup roller 4 to pick up a sheet of paper P, a paper sensor (not shown) to sense the sheets of paper P, a feed roller 5 to align a leading end of the picked-up paper P and transport it, a register sensor 6 to sense a timing driving the feed roller 5 to allow the feed roller 5 to align the leading end of the picked-up paper P, a guide 7 to guide the feed of paper P, and a discharging roller 8 and a discharging backup roller 12 to discharge the paper P.
The operation of the ink jet printer constructed as above will be explained as follows.
According to a print command from a computer, the pickup roller 4 picks up a sheet of paper P from the paper cassette 3, and transports it toward the feed roller 5 along the guide 7.
At this point, the register sensor 6 installed in front of the feed roller 5 is actuated by the paper P, and thereby a controller (not shown) calculates how long it takes the leading end of paper P to move from the register sensor 6 to an entrance of the feed roller 5, and then drives the pickup roller 4 for the calculated time, that is, until the leading end of paper P is curled and aligned at a nip between the feed roller 5 and a backup roller 10.
After the leading end of paper P is aligned, the controller stops the pickup roller 4, and at the same time, drives the feed roller 5 to move the paper P into a printing area under a nozzle 1a of the print head of the ink cartridge 1.
When the paper P is moved into the printing area, the carrier 2 moves the ink cartridge 1 right and left, so that the ink cartridge 1 can jet ink through the nozzle 1a of the print head to perform the printing operation.
When the printing is completed as above, the discharging roller 8 discharges the paper P, and the printing operation is finished.
But in such a conventional ink jet printer, since the paper cassette 3 of the paper feeding apparatus is integrally connected with a main body of the printer, there is a problem that a space for installing and mounting the paper cassette 3 is required, thereby increasing a size of the printer.
To solve the problem, as is shown in FIGS. 3A and 3B, there has been proposed another image forming device having a paper cassette 3′ which is mounted on a main body 20 of the printer when in use, and separated from the main body 20 and stored in a separate space when not in use.
This image forming device has an advantage that when the paper cassette 3′ is separated from the main body 20 and stored in the separate space, a size of the printer is reduced. But it is troublesome that for use, the paper cassette 3′ must be mounted on the main body 20.
Also, when the paper cassette 3′ is separated from the main body 20 and stored in the separate space, the paper cassette 3′ can be lost or damaged due to poor management or limitation of space.
To solve these problems, as is shown in FIGS. 4A and 4B, there has been proposed still another image forming device having a paper cassette or unit 3″ which is hinged on a front portion or a side portion of a main body 20′ of the printer. The hinged paper cassette 3″ is manually opened and closed, rather than being mounted on and separated from the main body 20′.
But with this image forming device, it is troublesome that for use, a user must manually open and close the paper cassette 3″. And as an additional problem, when sheets of paper P remain in the paper cassette 3″ after printing, the remaining sheets of paper must be stored in a separate space when the paper cassette 3″ is closed.